A trypsin-sensitive, cyclic nucleotide independent prokinase from rat brain supernatant contains a calmodulin-like subunit. It phosphorylates histone type II in a Ca++ dependent manner, and histone type H1 in a phospholipid dependent manner. It may phosphorylate tryptophan hydroxylase in a calmodulin dependent manner. It may phosphorylate synaptic plasma membrane in a calcium and calmodulin-dependent manner as well.